Downlink channel repetition for common search space sets

Abstract

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive an indication that a first common search space set and a second common search space set are linked for repetition of a downlink control channel that includes downlink control information associated with a random access procedure, scheduling of system information, or a paging procedure. The UE may monitor the first common search space set and the second common search space set for the downlink control information based at least in part on the indication. The UE may decode the downlink control information using at least one of a first physical downlink control channel candidate of the first common search space set or a second physical downlink control channel candidate of the second common search space set, where the first physical downlink control channel candidate is linked with the second physical downlink control channel candidate.

What is claimed is: 
     
         1 . An apparatus for wireless communications at a user equipment (UE), comprising:
 a processor;   memory coupled with the processor; and   instructions stored in the memory and executable by the processor to cause the apparatus to:
 receive an indication that a first common search space set is configured for a downlink control channel that includes first downlink control information associated with a random access procedure, scheduling of system information, or a paging procedure, the first common search space set being an only common search space set configured for the downlink control channel in accordance with a confirmatory rule pertaining to linked common search space sets and downlink control information messages associated with the random access procedure, the scheduling of system information, or the paging procedure; and 
 monitor the first common search space set for the downlink control channel based at least in part on the first common search space set being configured in accordance with the confirmatory rule. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the confirmatory rule is that the UE does not expect that a type 0, type 0a, type 1, or type 2 common search space set to be linked to another search space set. 
     
     
         3 . The apparatus of  claim 1 , wherein the confirmatory rule is that the UE does not expect that a common search space set having an index of zero is to be linked to another common search space set. 
     
     
         4 . An apparatus for wireless communication at a base station, comprising:
 a processor;   memory coupled with the processor; and   instructions stored in the memory and executable by the processor to cause the apparatus to:
 transmit, to a user equipment (UE), an indication that a first common search space set is configured for a downlink control channel that includes first downlink control information associated with a random access procedure, scheduling of system information, or a paging procedure, the first common search space set being an only common search space set configured for the downlink control channel in accordance with a confirmatory rule pertaining to linked common search space sets and downlink control information messages associated with the random access procedure, the scheduling of system information, or the paging procedure; 
 encode the first downlink control information in the first common search space set based at least in part on the first common search space set being configured in accordance with the confirmatory rule; and 
 transmit the encoded first downlink control information. 
   
     
     
         5 . The apparatus of  claim 4 , wherein the confirmatory rule is that the UE does not expect that a type 0, type 0a, type 1, or type 2 common search space set to be linked to another search space set. 
     
     
         6 . The apparatus of  claim 4 , wherein the confirmatory rule is that the UE does not expect that a common search space set having an index of zero is to be linked to another common search space set. 
     
     
         7 . An apparatus for wireless communications at a user equipment (UE), comprising:
 a processor;   memory coupled with the processor; and   instructions stored in the memory and executable by the processor to cause the apparatus to:
 receive an indication that a first common search space set and a second common search space set are linked for repetition of a downlink control channel that includes downlink control information associated with a random access procedure, scheduling of system information, or a paging procedure; 
 monitor the first common search space set and the second common search space set for the downlink control information based at least in part on the indication; and 
 decode the downlink control information using at least one of a first physical downlink control channel candidate of the first common search space set or a second physical downlink control channel candidate of the second common search space set, where the first physical downlink control channel candidate is linked with the second physical downlink control channel candidate. 
   
     
     
         8 . The apparatus of  claim 7 , wherein the instructions to receive the indication are executable by the processor to cause the apparatus to:
 receive a first control message that includes a configuration that links, for repetition, the first common search space set with the second common search space set; and   receive a second control message that indicates that the first common search space set is to be monitored for the downlink control channel based at least in part on the downlink control information being associated with one of the random access procedure, the scheduling of system information, or the paging procedure.   
     
     
         9 . The apparatus of  claim 7 , wherein the instructions to receive the indication are executable by the processor to cause the apparatus to:
 receive a control message that indicates that both the first common search space set and the second common search space set are linked and are to be monitored for the downlink control channel based at least in part on the downlink control information being associated with one of the random access procedure, the scheduling of system information, or the paging procedure.   
     
     
         10 . The apparatus of  claim 9 , wherein the instructions to receive the control message are executable by the processor to cause the apparatus to:
 receive a common physical downlink control channel configuration message that indicates that both a first index associated with the first common search space set and a second index associated with the second common search space set correspond to a same common search space set type.   
     
     
         11 . The apparatus of  claim 7 , wherein the instructions are further executable by the processor to cause the apparatus to:
 determine a number of downlink control channel candidates for the first common search space set and the second common search space set for a control channel element aggregation level of a set of control channel element aggregation levels, wherein the UE monitors the first common search space set and the second common search space set based at least in part on the determined number of downlink control channel candidates.   
     
     
         12 . The apparatus of  claim 11 , wherein the instructions to determine the number of downlink control channel candidates for the control channel element aggregation level are executable by the processor to cause the apparatus to:
 identify a mapping between the control channel element aggregation level and the number of downlink control channel candidates for the control channel element aggregation level; and   assign the number of downlink control channel candidates to both the first common search space set and the second common search space set.   
     
     
         13 . The apparatus of  claim 11 , wherein the instructions to determine the number of downlink control channel candidates for the control channel element aggregation level are executable by the processor to cause the apparatus to:
 identify a mapping between the control channel element aggregation level and the number of downlink control channel candidates for the control channel element aggregation level; and   assign a half of the number of downlink control channel candidates to both the first common search space set and the second common search space set.   
     
     
         14 . The apparatus of  claim 11 , wherein the instructions to determine the number of downlink control channel candidates for the control channel element aggregation level are executable by the processor to cause the apparatus to:
 identify a mapping between the control channel element aggregation level and the number of downlink control channel candidates for the control channel element aggregation level; and   assign the number of downlink control channel candidates to the first common search space set and the second common search space set based at least in part on whether the first common search space set and the second common search space set are positioned within a same transmission time interval.   
     
     
         15 . The apparatus of  claim 14 , wherein:
 the UE assigns half of the number of downlink control channel candidates to both the first common search space set and the second common search space set when the first common search space set and the second common search space set are positioned within the same transmission time interval, or; and   the UE assigns the number of downlink control channel candidates to both the first common search space set and the second common search space set when the first common search space set and the second common search space set are positioned within separate transmission time intervals.   
     
     
         16 . The apparatus of  claim 11 , wherein the instructions to determine the number of downlink control channel candidates for the control channel element aggregation level are executable by the processor to cause the apparatus to:
 identify a mapping between the control channel element aggregation level and the number of downlink control channel candidates for the control channel element aggregation level based at least in part on the first common search space set or the second common search space set having an index of zero.   
     
     
         17 . The apparatus of  claim 11 , wherein the instructions to determine the number of downlink control channel candidates for the control channel element aggregation level are executable by the processor to cause the apparatus to:
 determine the number of downlink control channel candidates for the control channel element aggregation level based at least in part on a search space set configuration corresponding to both the first common search space set and the second common search space set.   
     
     
         18 . The apparatus of  claim 11 , wherein the instructions are further executable by the processor to cause the apparatus to:
 determine a total number of downlink control channel candidates by determining the number for each control channel element aggregation level of the set of control channel element aggregation levels.   
     
     
         19 . The apparatus of  claim 7 , wherein the instructions are further executable by the processor to cause the apparatus to:
 receive an indication that the first common search space set has an index of zero;   receive an indication of a first configuration for the first common search space set in accordance with the first common search space set having the index of zero; and   receive in indication of a second configuration for the second common search space set that corresponds to the first configuration.   
     
     
         20 . The apparatus of  claim 7 , wherein the instructions are further executable by the processor to cause the apparatus to:
 receive an indication that the first common search space set has an index of zero, wherein the first common search space set is associated with one or more first monitoring occasions; and   monitor one or more second monitoring occasions of the second common search space set that map to the one or more first monitoring occasions of the first common search space set based in accordance with the first common search space set having the index of zero.   
     
     
         21 . The apparatus of  claim 20 , wherein the instructions are further executable by the processor to cause the apparatus to:
 refrain from monitoring a second monitoring occasion of the second common search space set that does not map to any of the one or more first monitoring occasions of the first common search space set.   
     
     
         22 . The apparatus of  claim 20 , wherein the instructions are further executable by the processor to cause the apparatus to:
 determine that the one or more second monitoring occasions of the second common search space set map to the one or more first monitoring occasion of the first common search space set in accordance with the first common search space set and the second common search space set being positioned within a same slot or within consecutive slots, a first quantity of the one or more first monitoring occasions relative to a second quantity of the monitoring occasions of the second common search space set, or a combination thereof.   
     
     
         23 . The apparatus of  claim 7 , wherein the instructions are further executable by the processor to cause the apparatus to:
 transmit an indication that the UE supports the repetition of the downlink control channel that includes downlink control information associated with the random access procedure, the scheduling of system information, the paging procedure, or a combination thereof.   
     
     
         24 . The apparatus of  claim 23 , wherein the instructions to transmit the indication are executable by the processor to cause the apparatus to:
 transmit the indication of support per radio network temporary identifier type, transmitting the indication of support of linkage of search space sets with search space set zero, transmitting the indication of support of inter-slot linkage, transmitting the indication of support of intra-slot linkage, transmitting the indication of support for UE-specific search space set linkage, transmitting the indication of support for type 3 search space set linkage, or a combination thereof.   
     
     
         25 . The apparatus of  claim 23 , wherein the instructions to transmit the indication are executable by the processor to cause the apparatus to:
 transmit a separate indication specifying support for each of type 0, type 0A, type 1, and type 2 downlink control channel common search space set linkage.   
     
     
         26 . The apparatus of  claim 23 , wherein the instructions are further executable by the processor to cause the apparatus to:
 receive, based at least in part on transmitting the indication, a first control message that includes a configuration that links, for repetition, the first common search space set with the second common search space set.   
     
     
         27 . The apparatus of  claim 7 , wherein both the first common search space set and the second common search space set are type 0 common search space sets associated with a system information radio network temporary identifier, a type 0A common search space sets associated with the system information radio network temporary identifier, type 1 common search space sets associated a random access radio network temporary identifier, a MsgB radio network temporary identifier, or a temporary cell rando network temporary identifier, or a type 2 common search space sets associated with a paging radio network temporary identifier. 
     
     
         28 . An apparatus for wireless communications at a base station, comprising:
 a processor;   memory coupled with the processor; and   instructions stored in the memory and executable by the processor to cause the apparatus to:
 transmit, to a user equipment (UE) an indication that a first common search space set and a second common search space set are linked for repetition of a downlink control channel that includes downlink control information associated with a random access procedure, scheduling of system information, or a paging procedure; 
 encode the downlink control information in a first downlink control channel candidate and a second downlink control channel candidate that is linked to the first downlink control channel candidate based at least in part on the indication; and 
 transmit, to the UE, the encoded downlink control information in the first common search space set that includes the first downlink control channel candidate and in the second common search space set that includes the second downlink control channel candidate. 
   
     
     
         29 . The apparatus of  claim 28 , wherein the instructions to transmit the indication are executable by the processor to cause the apparatus to:
 transmit a first control message that includes a configuration that links, for repetition, the first common search space set with the second common search space set; and   transmit a second control message that indicates that the first common search space set is to be monitored for the downlink control channel based at least in part on the downlink control information being associated with one of the random access procedure, the scheduling of system information, or the paging procedure.   
     
     
         30 . The apparatus of  claim 28 , wherein the instructions to transmit the indication are executable by the processor to cause the apparatus to:
 transmit a control message that indicates that both the first common search space set and the second common search space set are linked and are to be monitored for the downlink control channel based at least in part on the downlink control information being associated with one of the random access procedure, the scheduling of system information, or the paging procedure.